Luu, ViChi

Abstract [en]

This report is the documentation of a master’s thesis which was conducted at Scania CV AB in Södertälje. In this study, the benefits, challenges and conditions of using parametric CAD-models for aiding CFD-simulations and performance-optimization in the product development within internal combustion engines have been assessed. The goal of the thesis included developing and proposing a methodology for design engineers at Scania which will aid them in creating parametric CAD-models which are robust, flexible, comprehensible and intelligent. The study also included assessing the benefits and pre-requisites of such methodology with both practical and theoretical approaches. The ultimate goal of this entire study was to create value for the organization by reducing lead-time in the design process while promoting the production of high quality products.

A case-based approach was applied in the study in which modeling strategies resulting from practical investigations and analyzing existing methodologies were implemented on a CAD-model representing the gas-volume of a turbine volute. The chosen strategies were evaluated and subsequently documented as a part of the methodology or discarded depending on its support for the parameterization. The final methodology itself was evaluated based on the quality of the parameterized CAD-model, the time required to create the model and its compatibility to the present design process at Scania CV AB. Finally the methodology was discussed with respect to the different evaluations, and the defined research questions were discussed and answered. The results of the thesis revealed that if parametric CAD-models are made in a structured, standardized and conscious manner, they are able to be highly robust and flexible which gives the models the ability to assume a big set of different forms. The methodology is recommended to be tested in a pilot project and be implemented through internal courses at the company.

It was concluded that a methodology which aids the design engineers in creating parametric CAD-models will be the key towards implementing parametric CAD-models in the company and also enabling the many benefits of parameterization, which includes reduced lead-time, enhanced component performance, increased knowledge about the component, and promotion of collaboration among engineers. It was also concluded that parametric models are best suited when the existing design freedom is big and when the time permits performance analyses via optimizations, while challenges include ensuring that the model is parameterized correctly with respect to the CFD-engineers’ wishes while taking into account the requirements from other disciplines. Therefore it is very important to establish a communication between the different engineers. Ultimately, when parametric models are established in the organization, they are recommended to be implemented eventually in both short-term and long-term projects within Scania for its beneficial properties.